Multi-gear transmission system shiftable under load

摘要

A gear-shifting mechanism for an automotive transmission or the like comprises a first power train with at least two cascaded ratio-changing couplers inserted between an input shaft and an output shaft, the cascaded couplers being bypassed by a second power train which is normally disengaged but is engageable during shiftovers to interconnect the two shafts with at least one step-down ratio different from any of the speed ratios that can be established by the first power train. The two or possibly more power trains may be constituted by planetary-gear assemblies. One or more of the cascaded couplers could be divided into parallel sections to be alternatively clutched in.